FDA grants Fast Track designation to TTK inhibitor for the treatment of ER+/HER2- breast cancer

The US biotech company Treadwell Therapeutics has announced the FDA Fast Track designation of an inhibitor of Threonine Tyrosine Kinase for the treatment of patients with ER+/HER2- advanced breast cancer.

Globally, breast cancer is the world’s most prevalent cancer and the second leading cause of cancer death in women in many countries.

The ER+/HER2- subtype is the most common subtype of breast cancer, accounting for 68 per cent of all breast cancer types, with nearly 1.2 million women living with the disease in the US alone.

Standard of care for ER+ patients is CDK4/6 inhibitors in combination with endocrine therapies, which have been very successful in prolonging survival for this patient population.

However, resistance to this treatment occurs within a median of two years. As a result, the ER+ population resistant to this standard of care is growing and is an unmet medical need requiring new treatment options.

CFI-402257 is an orally active, highly selective small molecule inhibitor for TTK – the core component of the spindle assembly checkpoint – and can help adult patients with advanced breast cancer after disease progression on prior CDK4/6 inhibitors and endocrine therapy.

“There is an urgent need for new, safe and efficacious therapies to treat ER+/HER2- breast cancer, particularly when standard of care regimens fail,” said Dr Mark Bray, Treadwell CSO and co-founder.

“CFI-402257 [the TTK inhibitor] has shown early signs of durable activity with a manageable safety profile, as a monotherapy and in combination with fulvestrant in ER+/HER2- breast cancer patients that have failed CDK4/6 inhibitors.

“We are thankful for the Fast Track Designation granted by the FDA and look forward to the continued development of CFI-402257 in ER+/HER2- breast cancer.”

The FDA Fast Track designation seeks to streamline the development and accelerate the review of new agents with potential to treat serious or life-threatening diseases and that potentially address an unmet medical need.

Drugs that are granted this designation can have more frequent interactions with the FDA, as well as potential pathways for expedited approval.